--> FOAM FATAL ERROR : This mesh contains patches of type empty but is not 1D or 2D
by virtue of the fact that the number of faces of this
empty patch is not divisible by the number of cells.#0 Foam::error::printStack(Foam:stream&)
#1 Foam::error::abort()
#2 Foam::emptyFvPatchField<double>::updateCoeffs()
#3 Foam::fvPatchField<double>::evaluate()
#4 Foam::GeometricField<double,>::GeometricBoundaryFi eld::evaluate()
#5 Foam::tmp<foam::geometricfield<double,> > Foam::fvc::surfaceIntegrate<double>(Foam::Geometri cField<double,> const&)
#6 Foam::tmp<foam::geometricfield<double,> > Foam::fvc::div<double>(Foam::GeometricField<double ,> const&)
#7 main
#8 __libc_start_main
#9 __gxx_personality_v0 at /usr/src/packages/BUILD/glibc-2.3/csu/../sysdeps/i386/elf/start.S:122

From function emptyFvPatchField<type>::updateCoeffs()
in file fields/fvPatchFields/basicFvPatchFields/empty/emptyFvPatchField.C at line 139.

empty b.c. can only be used for 1D or 2D geometry. In simple terms your mesh has be createable by extrusion. Front and back then can be empty but it is up to you to guarantee no flow/pressure gradient in that direction. See the lid-driven tutorial as an example.